const fs = require('fs');
const path = require('path');
const { v4: uuidv4 } = require('uuid');
const { validateFile, getFileType } = require('../utils/fileValidation');
const { formatFileSize } = require('../utils/helpers');

exports.uploadFile = async (req, res) => {
  try {
    if (!req.file) {
      return res.status(400).json({ error: 'No file provided' });
    }

    const file = req.file;
    
    // Validate file
    const fileCategory = validateFile(file);

    // Generate file metadata
    const fileData = {
      id: uuidv4(),
      originalName: file.originalname,
      fileName: file.filename,
      fileSize: file.size,
      mimeType: file.mimetype,
      url: `/uploads/${file.filename}`,
      uploaderId: req.user.userId,
      uploadedAt: new Date()
    };

    // Generate thumbnail for images (simplified - in production use sharp/gm)
    if (fileCategory === 'image') {
      fileData.thumbnail = `/uploads/${file.filename}`; // Same file for demo
    }

    res.json({
      message: 'File uploaded successfully',
      file: fileData
    });
  } catch (error) {
    console.error('❌ File upload error:', error);
    res.status(400).json({ error: error.message });
  }
};

exports.getFile = async (req, res) => {
  try {
    const { filename } = req.params;
    const filePath = path.join(__dirname, '../../uploads', filename);

    // Check if file exists
    if (!fs.existsSync(filePath)) {
      return res.status(404).json({ error: 'File not found' });
    }

    // Set appropriate headers
    const ext = path.extname(filename).toLowerCase();
    const mimeTypes = {
      '.jpg': 'image/jpeg',
      '.jpeg': 'image/jpeg',
      '.png': 'image/png',
      '.gif': 'image/gif',
      '.webp': 'image/webp',
      '.pdf': 'application/pdf',
      '.txt': 'text/plain',
      '.mp3': 'audio/mpeg',
      '.wav': 'audio/wav',
      '.ogg': 'audio/ogg'
    };

    res.setHeader('Content-Type', mimeTypes[ext] || 'application/octet-stream');
    res.setHeader('Content-Disposition', `inline; filename="${filename}"`);

    // Stream file
    const fileStream = fs.createReadStream(filePath);
    fileStream.pipe(res);
  } catch (error) {
    console.error('❌ Get file error:', error);
    res.status(500).json({ error: 'Server error retrieving file' });
  }
};

exports.cleanupOrphanedFiles = async (req, res) => {
  try {
    // This would typically be a cron job
    const uploadsDir = path.join(__dirname, '../../uploads');
    const files = fs.readdirSync(uploadsDir);
    
    const orphanedFiles = [];
    const oneWeekAgo = new Date(Date.now() - 7 * 24 * 60 * 60 * 1000);

    for (const file of files) {
      const filePath = path.join(uploadsDir, file);
      const stats = fs.statSync(filePath);
      
      // Check if file is older than 1 week and not referenced in any message
      if (stats.mtime < oneWeekAgo) {
        const messageWithFile = await Message.findOne({ 'attachment.fileName': file });
        if (!messageWithFile) {
          orphanedFiles.push(file);
          fs.unlinkSync(filePath);
        }
      }
    }

    res.json({
      message: `Cleaned up ${orphanedFiles.length} orphaned files`,
      orphanedFiles
    });
  } catch (error) {
    console.error('❌ Cleanup error:', error);
    res.status(500).json({ error: 'Server error during cleanup' });
  }
};